Outback Tire Size

Discussion in 'Subaru Outback' started by BobN, Jul 26, 2005.

  1. BobN

    BobN Guest

    The OEM spec for my 98 OBL is 205/70-15. Would it cause problems to
    substitute 215/70-15?

    I am buying a set of Goodyear Tripletreads. According to the dealer's
    website, the diameter of the 205 tire is 26.3" and the diameter of the 215
    is 26.9".

    I absolutely don't want to have problems with these, but wonder if the .6"
    extra diameter might work. It would certainly help traction to have the
    slightly wider rubber.

    Thanks.
     
    BobN, Jul 26, 2005
    #1
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  2. BobN

    ep6757 Guest

    To keep the tire diameter and revs per mile similar when increasing tire
    width, one normally goes down in aspect ration. So, have you looked
    into 215/65-15's? You can compare sizes at www.tirerack.com.

    Ed P
     
    ep6757, Jul 26, 2005
    #2
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  3. BobN

    Ed P Guest

    According to tirerack, stock-size 205/70TR15 Triple Treads have a revs
    per mile of 793. The 215/65TR15 come in at 803, causing your speedo to
    read 1.26% faster. The 215/70TR15 come in at 777 revs/mile, so speedo
    would run 2% slower.

    Ed P
     
    Ed P, Jul 26, 2005
    #3
  4. BobN

    Tcassette Guest

    Actually, your traction would be decreased under certain situations with
    the wider tread, such as ice/snow and other very wet conditions where
    weight per square inch can count as much as larger gripping surface.
    Because the Tripletreads come in the OEM size and the ones you are
    considering have only 0.4-inch wider tread, why ask for problems such as
    inaccurate speedometer or possible wheelwell interference when turning?
     
    Tcassette, Jul 27, 2005
    #4
  5. Assuming tires on a particular vehicle are at the same inflation
    pressure, the weight per square inch is the same regardless of the size
    of tire. Putting on a wider tire just makes the contact patch wider and
    not as deep front to back. Lack of traction on a wider tire comes from a
    tendency to ride over water, snow, or ice, rather than cut through it.
     
    Dave Morrison, Jul 27, 2005
    #5
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